OpenWrt/DD-WRT installation on malfunction router

[axodus]

tl;dr Is it possible to install ,config and use OpenWrt/DD-WRT firmware on a wireless router with no Ethernet connectivity?
(serial and WiFi working)

hi,
I've got a TP-link TL-WR841N router which had his Ethernet ports fried by an electric surge.
The router WiFi link still function, just no Ethernet connectivity of any kind.
I want to re purpose the router hardware so I can establish a serial communication over WiFi.

I read about the option of installing custom firmware to the route such as OpenWrt with net2serin order
to enable his on board serial port. I'm looking for someone who did this kind of hack before for some advice.

I can install OpenWrt by connecting to the router web interface through WiFi,
but cannot use Ethernet to continue with the setup afterwards.
will the serial interface or WiFi connection be working right after OpenWrt installation?
or if not, can I preconfig the OpenWrt image to work right out of the box?
The same questions for DD-WRT.

thanks,
axodus.

[MS3FGX]

WiFi won't work out of the box, as it won't be configured against your AP. In fact, in OpenWRT will have WiFi completely disabled by default.

So you're options would be to build your own image of OpenWRT for this device, where you can put in your own configuration files. This would get the router started up to a pre-configured state against your AP, but there is a bit of risk involved there; as if you got any of the configuration wrong, you'd probably have a brick.

Really, the safest thing would be to install and configure over serial. Of course, that means you'll need to get a level shifter hooked up to it.

[GaspingSpark]

You could always try replacing the isolation transformers (Black box near the ports, probably says GROUPTEK or MNC), those are designed to blow in the event of a surge and protect the rest of the circuit. There are two separate ones for the internal LAN ports and a smaller one for the WAN port. I'm surprised both the internal LAN ones blew and the WAN one stayed OK. Maybe there's just an MOV (Metal Oxide Varisitor) shorted to ground.